He cannot move him.

He'll seize him by the hind legs, still he cannot move him.
Then he will hear a voice say, 'Leave him alone, you can't move him.' The hunter will look down, see nothing but a rainbow at the foot of the tree.

Wonderingly he'll come down, and immediately the Euloowayi, who have been in the form of the opossum in the tree and the rainbow on the ground, seize him, tear him open with their long nails, take out all his fat, stuff him up again with grass and leaves, and send him back to the camp.

When he reaches there, he starts scolding every one.

Probably they guess by his violent words and actions that he is a victim of the Euloowayi.